2 * Copyright (c) 1980, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)param.c 8.3 (Berkeley) 8/20/94
39 * $FreeBSD: src/sys/kern/subr_param.c,v 1.42.2.10 2002/03/09 21:05:47 silby Exp $
40 * $DragonFly: src/sys/kern/subr_param.c,v 1.7 2005/06/26 22:03:22 dillon Exp $
43 #include "opt_param.h"
44 #include "opt_maxusers.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
51 #include <machine/vmparam.h>
54 * System parameter formulae.
60 #define NPROC (20 + 16 * maxusers)
65 #define MAXFILES (maxproc * 16)
67 #ifndef MAXPOSIXLOCKSPERUID
68 #define MAXPOSIXLOCKSPERUID (maxusers * 64) /* Should be a safe value */
74 int ustick; /* tick interval in microseconds */
75 int nstick; /* tick interval in nanoseconds */
76 int maxusers; /* base tunable */
77 int maxproc; /* maximum # of processes */
78 int maxprocperuid; /* max # of procs per user */
79 int maxfiles; /* system wide open files limit */
80 int maxfilesrootres; /* descriptors reserved for root use */
81 int minfilesperproc; /* per-proc min open files (safety) */
82 int maxfilesperproc; /* per-proc open files limit */
83 int maxfilesperuser; /* per-user open files limit */
84 int maxposixlocksperuid; /* max # POSIX locks per uid */
85 int ncallout; /* maximum # of timer events */
86 int mbuf_wait = 32; /* mbuf sleep time in ticks */
89 long maxswzone; /* max swmeta KVA storage */
90 long maxbcache; /* max buffer cache KVA storage */
91 u_quad_t maxtsiz; /* max text size */
92 u_quad_t dfldsiz; /* initial data size limit */
93 u_quad_t maxdsiz; /* max data size */
94 u_quad_t dflssiz; /* initial stack size limit */
95 u_quad_t maxssiz; /* max stack size */
96 u_quad_t sgrowsiz; /* amount to grow stack */
99 * These have to be allocated somewhere; allocating
100 * them here forces loader errors if this file is omitted
101 * (if they've been externed everywhere else; hah!).
106 * Boot time overrides that are not scaled against main memory
112 TUNABLE_INT_FETCH("kern.hz", &hz);
113 stathz = hz * 128 / 100;
115 ustick = 1000000 / hz;
116 nstick = 1000000000 / hz;
117 /* can adjust 30ms in 60s */
118 ntp_default_tick_delta = howmany(30000000, 60 * hz);
120 #ifdef VM_SWZONE_SIZE_MAX
121 maxswzone = VM_SWZONE_SIZE_MAX;
123 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
124 #ifdef VM_BCACHE_SIZE_MAX
125 maxbcache = VM_BCACHE_SIZE_MAX;
127 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
129 TUNABLE_QUAD_FETCH("kern.maxtsiz", &maxtsiz);
131 TUNABLE_QUAD_FETCH("kern.dfldsiz", &dfldsiz);
133 TUNABLE_QUAD_FETCH("kern.maxdsiz", &maxdsiz);
135 TUNABLE_QUAD_FETCH("kern.dflssiz", &dflssiz);
137 TUNABLE_QUAD_FETCH("kern.maxssiz", &maxssiz);
139 TUNABLE_QUAD_FETCH("kern.sgrowsiz", &sgrowsiz);
143 * Boot time overrides that are scaled against main memory
146 init_param2(int physpages)
151 * Calculate manually becaus the VM page queues / system is not set up yet
153 limsize = (size_t)physpages * PAGE_SIZE;
154 if (limsize > KvaSize)
156 limsize /= 1024 * 1024; /* smaller of KVM or physmem in MB */
158 /* Base parameters */
160 TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
162 maxusers = limsize / 8; /* ~384 per 3G */
169 * The following can be overridden after boot via sysctl. Note:
170 * unless overriden, these macros are ultimately based on maxusers.
172 * Limit maxproc so that kmap entries cannot be exhausted by
176 TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
179 if (maxproc > limsize * 21)
180 maxproc = limsize * 21;
183 * Maximum number of open files
186 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
191 * Limit file descriptors so no single user can exhaust the
194 * WARNING: Do not set minfilesperproc too high or the user
195 * can exhaust the system with a combination of fork()
196 * and open(). Actual worst case is:
198 * (minfilesperproc * maxprocperuid) + maxfilesperuser
200 maxprocperuid = maxproc / 4;
201 if (maxprocperuid < 128)
202 maxprocperuid = maxproc / 2;
204 maxfilesperproc = maxfiles / 4;
205 maxfilesperuser = maxfilesperproc * 2;
206 maxfilesrootres = maxfiles / 20;
209 * Severe hack to try to prevent pipe() descriptors from
210 * blowing away kernel memory.
212 if (KvaSize <= (vm_offset_t)(1536LL * 1024 * 1024) &&
213 maxfilesperuser > 20000) {
214 maxfilesperuser = 20000;
217 maxposixlocksperuid = MAXPOSIXLOCKSPERUID;
218 TUNABLE_INT_FETCH("kern.maxposixlocksperuid", &maxposixlocksperuid);
221 * Unless overriden, NBUF is typically 0 (auto-sized later).
224 TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
226 ncallout = 16 + maxproc + maxfiles;
227 TUNABLE_INT_FETCH("kern.ncallout", &ncallout);